Generally, when testing an operation state and the like of an information processing device, a testing instrument is externally connected to the information processing device. For example, a testing instrument (external processing device) is connected to a vehicle fault diagnosis device described in Patent Document 1 via a communication path (external communication path) when the vehicle fault diagnosis device conducts a function test on the information processing device including the diagnosis device. The testing instrument is supplied by the information processing device with results and the like of analysis regarding fault information in the information processing device and, in return, commands the information processing device to add fault cause identification means based on a tree principle for identifying the cause for faults in the information processing device, deletes the added fault cause identification means from the information processing device, or sets up for transferring the information processing device into a test mode. As a result, a test directed by the testing instrument can be conducted in the information processing device as necessary and, when the test is unnecessary, the testing instrument can be removed from the information processing device.
Further, in development of an information processing device, it is indispensable to execute software in the device while monitoring the execution state of the software in real time and also perform online debugging so that the software can be modified as necessary while being executed. Like the vehicle fault diagnosis device described in Patent Document 1, such online debugging is accompanied by externally connecting a testing instrument, in this case, a “debugging instrument” to the information processing device. That is, an online debugging device provided separately from the information processing device is connected to the information processing device via a debugging communication path.
For example, when debugging a navigation system, which is one of a vehicle-mounted information processing device, during its development, as shown in FIG. 12(a), a debug daemon 61, which is software for providing the navigation system 60A with debug functions, is connected to a debug device 50 outside a vehicle in a communicable manner. Then, in the navigation system 60A, between the debug daemon 61 and the debug device 50, a communication path that enables communication based on a protocol generated by TCP/IP62 is established via an Ethernet interface 64 or the like that is made usable by an Ethernet driver 63.